Canon EOS 80D - Manual (Page 178)

3 Correction of Lens Peripheral Illumination and AberrationsN
178
Cautions for Lens Correction
 Peripheral illumination correction, chromatic aberration correction, and
distortion correction cannot be applied to JPEG images already taken.
 When using a non-Canon lens, setting the corrections to [Disable] is
recommended, even if [Correction data available] is displayed.
 If you use the magnified view during Live View shooting, the peripheral
illumination correction will not be reflected in the image displayed on the
screen.
 The correction amount will be less if the lens used does not have
distance information.
Notes for Lens Correction
 If the effect of the correction is not visible, magnify the image after
shooting and check it again.
 Corrections can be applied even when an Extender or Life-size
Converter is attached.
 If the correction data for the attached lens is not registered to the
camera, the result will be the same as when the correction is set to
[Disable].